1. Field of the Inventive Subject Matter
The inventive subject matter relates to novel methods for treating oral cancers, comprising administration of a composition comprising therapeutically effective amounts of supercritical extracts of rosemary, turmeric, oregano and ginger; and therapeutically effective amounts of hydroalcoholic extracts of holy basil, ginger, turmeric, Scutellaria baicalensis, rosemary, green tea, huzhang, Chinese goldthread, and barberry. The inventive subject matter further relates to methods for modulating expression of LTB4 by administration of an effective amount of said compositions.
2. Background
Oral cancers. 30,000 Americans will be diagnosed with oral or pharyngeal cancer this year. It will cause over 8,000 deaths, killing roughly 1 person per hour, 24 hours per day. Of those 30,000 newly diagnosed individuals, only half will be alive in 5 years. This is a number which has not significantly improved in decades. The death rate for oral cancer is higher than that of cervical cancer, Hodgkin's disease, cancer of the brain, liver, testes, kidney, or skin cancer (malignant melanoma). If you expand the definition of oral cancers to include cancer of the larynx, for which the risk factors are the same, the numbers of diagnosed cases grow to 41,000 individuals, and 12,500 deaths per year in the US alone. Worldwide the problem is much greater, with over 350,000 to 400,000 new cases being found each year.
The death rate associated with this cancer is particularly high due to the cancer being routinely discovered late in its development. Often it is only discovered when the cancer has metastasized to another location, most likely the lymph nodes of the neck. Prognosis at this stage of discovery is significantly worse than when it is caught in a localized area. Besides the metastasis, at these later stages, the primary tumor has had time to invade deep into local structures. Oral cancer is particularly dangerous because it has a high risk of producing second, primary tumors. This means that patients who survive a first encounter with the disease, have up to a 20 times higher risk of developing a second cancer. This heightened risk factor can last for 5 to 10 years after the first occurrence. There are several types of oral cancers, but 90% are squamous cell carcinomas.
Understanding the causative factors of cancer will contribute to prevention of the disease. Age is frequently named as a risk factor for oral cancer, as most of the time it occurs in those over the age of 40. The age of diagnosed patients may indicate a time component in the biochemical or biophysical processes of aging cells that allows malignant transformation, or perhaps, immune system competence diminishes with age.
However, it is likely that the accumulative damage from other factors, such as tobacco use, are the real culprits. It may take several decades of smoking for instance, to precipitate the development of a cancer. Having said that, tobacco use in all its forms is number one on the list of risk factors. At least 75% of those diagnosed are tobacco users. When you combine tobacco with heavy use of alcohol, your risk is significantly increased, as the two act synergistically. Those who both smoke and drink, have a 15 times greater risk of developing oral cancer than others.
Tobacco and alcohol are essentially chemical factors, but they can also be considered lifestyle factors, since we have some control over them. Besides these, there are physical factors such as exposure to ultraviolet radiation. This is a causative agent in cancers of the lip, as well as other skin cancers. Cancer of the lip is one oral cancer whose numbers have declined in the last few decades. This is likely due to the increased awareness of the damaging effects of prolonged exposure to sunlight, and the use of sunscreens for protection. Another physical factor is exposure to x-rays. Radiographs regularly taken during examinations, and at the dental office, are safe, but remember that radiation exposure is accumulative over a lifetime. It has been implicated in several head and neck cancers.
Biological factors include viruses and fungi, which have been found in association with oral cancers. The human papilloma virus, particularly HPV16 and 18, have been implicated in some oral cancers. HPV is a common, sexually transmitted virus, which infects about 40 million Americans. There are about 80 strains of HPV, most thought to be harmless. But 1% of those infected, have the HPV16 strain which is a causative agent in cervical cancer, and now is linked to oral cancer as well. There are other risk factors which have been associated with oral cancers, but have not yet been definitively shown to participate in their development. These include lichen planus, an inflammatory disease of the oral soft tissues.
There are studies which indicate a diet low in fruits and vegetables could be a risk factor, and that conversely, one high in these foods may have a protective value against many types of cancer.
After a definitive diagnosis has been made and the cancer has been staged, treatment may begin. Treatment of oral cancers is ideally a multidisciplinary approach involving the efforts of surgeons, radiation oncologists, chemotherapy oncologists, dental practitioners, nutritionists, and rehabilitation and restorative specialists. The actual curative treatment modalities are usually surgery and radiation, with chemotherapy added to decrease the possibility of metastasis, to sensitize the malignant cells to radiation, or for those patients who have confirmed distant metastasis of the disease.
Based on 1991 National Cancer Institute Surveillance, Epidemiology, and End Results data, the overall incidence and mortality rates for oral and pharyngeal cancer combined are 10.4 per 100,000 population and 2.9 per 100,000 population, respectively. The annual incidence of 15.7 per 100,000 for males far exceeds the rate of 6.0 per 100,000 for females. (1)
Mortality rates show similar differentials: 4.5 per 100,000 per year for males, 1.7 per 100,000 per year for females. This gender difference is also evident in the lifetime risks of developing oral cancer: 1.5% for males and 0.7% for females (based on 1989-91 incidence rates).
5-lipoxygenase and 5-lipoxygenase Inhibitors. The 5-lipoxygenase (5-LO) pathway is one of at least four lipoxygenase pathways of arachidonic acid metabolism. The 5-lipoxygenase pathway consists of enzymes that regulate a series of biochemical reactions that result in the transformation of arachidonic acid to leukotriene A4, which can then be further metabolized to leukotriene B4 or to leukotriene C4. Activation of the 5-LO pathway leads to the biosynthesis of proinflammatory leukotriene lipid mediators, while inhibition of the 5-LO pathway may have anti-inflammatory effects.
Some compounds which inhibit 5-lipoxygenase have been described in U.S. Pat. Nos. 6,653,311, 6,455,541, 6,399,105, 6,121,323, 5,342,838, 5,298,514, 5,145,861, 5,130,483, 4,933,329, and 4,731,382. Drugs such as MK-886 (3-(1-(4-chlorobenzyl)-3-tert-butyl-thio-5-isopropylindol-2-yl)-2,2-dimethyl propanoic acid), L-656,224 ((7-chloro-2-[4-methoxypentyl]methyl)-3-methyl-5-propyl-4-benzofuranol), pentacyclic triterpene acetyl-11-keto-β-boswellic acid, PF-5901, Zileuton, and tepoxalin are intended to selectively inhibit 5-lipoxygenase. However, these drugs appear to have long term side effects. There is thus a continuing need for 5-lipoxygenase inhibitors which avoid side effects associated with current compositions.
Cyclooxygenase and Cyclooxygenase Inhibitors. Cyclooxygenase is an enzyme-protein complex with a variety of biochemical actions. There are at least three primary COX isoenzymes, COX-1, COX-2, and COX-3. COX-1 is a constitutive enzyme, produced at a reasonably consistent level at all times. It plays an important role in, for example, gastrointestinal protection, kidney function, and the aggregation of blood platelets. COX-2 production is not constant; it varies depending on signals from various biochemical catalysts. For example, in the case of arthritis inflammation and pain, COX-2 responds to tissue damage by oxidizing arachidonic acid, creating prostaglandins which in turn produce local inflammation. COX-3 has been identified relatively recently (Chandrasekharan, et al., PNAS U.S.A., 99(21):13926-31 (2002)). In humans, COX-3 mRNA is expressed most abundantly in the cerebral cortex and heart tissues. COX-3 activity is selectively inhibited by analgesic/antipyretic drugs. It has been suggested that inhibition of COX-3 could represent a mechanism by which these drugs decrease pain and possibly fever.
Prostaglandins play a major role in the inflammatory process and the inhibition of prostaglandin production, especially production of PGG2, PGH2, and PGE2, has been a common target of anti-inflammatory drug discovery. However, common non-steroidal anti-inflammatory drugs (hereinafter referred to as “NSAIDs”) that are active in reducing the prostaglandin-induced pain and swelling associated with the inflammation process are also active in affecting other prostaglandin-regulated processes not associated with the inflammation process.
NSAIDs have been found to prevent the production of prostaglandins by inhibiting enzymes in the human arachidonic acid/prostaglandin pathway, including the cyclooxygenase enzymes. Traditional non-steroidal anti-inflammatory drugs, such as aspirin, work by inhibiting both COX-1 and COX-2. Thus, non-specific NSAIDs can have a damaging effect on the gastrointestinal tract, kidneys, and liver; blocking COX-1 can make the stomach lining more vulnerable, and reduced thromboxane production thins the blood, making gastrointestinal hemorrhage more likely, and may cause inadequate regulation of cellular immune functions and the secretion of various cytokines. The use of high doses of most common NSAIDs can produce severe side effects, including life threatening ulcers, that limit their therapeutic potential.
COX-2 is associated with inflammation and provides a viable target of inhibition which more effectively reduces inflammation and produces fewer and less drastic side effects. Thus, researchers have been motivated to develop selective COX-2 inhibitors to reduce inflammation and relieve pain without the gastrointestinal damage brought on by inhibiting COX-1. In addition, the current scientific understanding in the art suggests that COX-2 inhibition may serve an important function in promoting normal cell growth in the colon, pancreas, breast tissue, and other organ systems.
Some compounds which selectively inhibit cyclooxygenase-2 have been described in U.S. Pat. Nos. 5,380,738, 5,344,991, 5,393,790, 5,434,178, 5,474,995, 5,510,368 and WO documents WO96/06840, WO96/03388, WO96/03387, WO96/25405, WO95/15316, WO94/15932, WO94/27980, WO95/00501, WO94/13635, WO94/20480, and WO94/26731.
Drugs such as valdecoxib, celecoxib, and rofecoxib are intended to selectively inhibit COX-2 with minimal effect on COX-1. However, despite the emphasis on COX-2 inhibition, even these drugs appear to have serious long term side effects, such as the breakdown in digestive protective mucus and prevention of normal healing processes. There is thus a continuing need for more specific and non-specific COX-2 inhibitors which avoid side effects associated with COX-1 inhibition.
LTB4. Leukotriene (LT) biosynthesis occurs mainly in granulocytes, monocytes/macrophages and mast cells and an orchestrated interplay between several key enzymes is crucial for efficient formation of leukotrienes, which are proinflammatory mediators released mainly from myeloid cells. 5-Lipoxygenase (5-LO) plays an essential role in the biosynthesis of leukotrienes. As shown in FIG. 1, on cell stimulation elevated Ca2+ levels and activated signal transduction cascades activate 5-lipoxygenase (5-LO) and lead to the release of arachidonic acid (AA) from phospholipids by phospholipase A2 (PLA2). AA is metabolized by 5-LO to the unstable intermediate LTA4, that can be converted to LTB4 by LTA4 hydrolase, or conjugated with glutathione to LTC4 by LTC4 synthase, depending on the enzymes present.
The biological actions of LTs are mediated by specific receptors. LTs are potent biological mediators in the pathophysiology of inflammatory diseases and host defense reactions. LTB4 is a potent chemotactic and chemokinetic mediator stimulating the immigration and activation of granulocytes, leading to adherence of granulocytes to vessel walls, degranulation, release of superoxide and lysosomal enzymes, and augments phagocytosis of neutrophils and macrophages. It exerts its effects via binding to the BLT1 and BLT2 receptors. In addition, LTB4 binds and activates the peroxisome proliferator-activated receptor-γ, a transcription factor that mediates anti-inflammatory actions. In lymphocytes, LTB4 stimulates the secretion of IgE, IgG and IgM and the expression of low-affinity receptors for IgE, and has been connected to increased interleukin production, transcription, and neutrophil-dependent hyperalgesia. These properties suggest a significant role for LTB4 in the pathogenesis of inflammatory diseases such as arthritis, psoriasis, inflammatory bowel disease, and asthma.
Natural COX-2 Inhibitors. Several herbs have been found to inhibit the COX-2 enzyme. For example, holy basil has been found to possess significant anti-inflammatory properties and is capable of blocking both the cyclooxygenase and lipoxygenase pathways of arachidonate metabolism. Ursolic acid and oleanolic acid, two of the recognized phytonutrients of holy basil, have been found to have a significant COX-2 inhibitory effect.
Similarly, shogaols and gingerols, pungent components of ginger, have been found to inhibit cyclooxygenase. Eugenol, another active constituent of several medical herbs, has also been found to be a 5-lipoxygenase inhibitor and to possess potent anti-inflammatory and/or anti-rheumatic properties.
Scutellaria baicalensis also has been found to inhibit the COX-2 enzyme. According to the USDA database, green tea contains six constituents having cyclooxygenase-inhibitor activity. According to the Napralert database, green tea contains fifty one constituents having anti-inflammatory activity. The polyphenols in green tea were found to cause a marked reduction in COX-2. Flavan-3-ol derivatives (+)-catechin, also present in green tea, have been reported to be COX-1 and COX-2 inhibitors. In addition, salicylic acid, another constituent of green tea, also has been found to be a COX-2 inhibitor.
Berberine, found in barberry and Chinese goldthread, has also been found to inhibit COX-2 without inhibiting COX-1 activity.
In U.S. Pat. No. 6,387,416, Applicants disclosed the inventive compositions and their use for reducing inflammation.
The contents of U.S. Pat. No. 6,387,416 are hereby incorporated by reference in their entirety. Surprisingly, as discussed in greater detail below, it has been determined that the inventive compositions are useful for treating oral cancers as well.
Use of COX-2 Inhibitors for Treating Cancer. It has been postulated that COX-2 inhibitors may be useful for treating cancer. Yet only a very few patents actually disclose the use of COX-2 inhibitors for treating any cancers. In U.S. Pat. No. 5,466,823 to Talley, et al., (Pyrazol-1-yl)benzene sulfonamides are disclosed as inhibitors of cyclooxygenase-2, and for use in the treatment of inflammation, arthritis, and pain, and as being useful for preventing colon cancer. However, their use for actually treating colon cancer or for treating or preventing other neoplasias is not disclosed.
U.S. Pat. No. 6,469,040 to Seibert, et al., discloses a method of using a specific, disclosed class of cyclooxygenase-2 inhibitor derivatives in preventing and treating epithelial cell neoplasia in a subject.
U.S. Pat. No. 6,534,540 to Kindness, et al., discloses a combination of the proprietary HMG-CoA reductase inhibitor lovastatin and the proprietary COX-2 inhibitor rofecoxib for the treatment of cancer, especially oral cancers, and a method of treatment of cancer, especially oral cancers, by administering that combination.
Table 1 depicts data on the inhibitory effects of administration of Zileuton and Celecoxib on the incidence of squamous cell carcinoma on DMBA-induced oral carcinogenesis and the levels of LTB4 and PGE2 in the hamster cheek pouch model.
TABLE 1Visible tumorsVolumeGroupTreatmentn% (n)(mm3)Papilloma, % (n)SCC, % (n)ANegative control15————BPositive control2684.689.2 ± 76.2 53.876.9 (2.96 ± 2.12) (0.96 ± 1.02) (1.68 ± 1.43) C3% Zileuton2458.339.9 ± 48.0†37.545.8‡(1.08 ± 1.4)‡(0.56 ± 0.66) (0.56 ± 0.66)*D6% Zileuton28 4.6422.9 ± 31.4†32.132.1†(0.68 ± 1.20)*(0.41 ± 0.58)‡(0.45 ± 0.72)†E3% Celecoxib2661.542.2 ± 41.2†69.257.6 (1.25 ± 1.41) (0.68 ± 0.47)‡(0.88 ± 0.88)‡F6% Celecoxib24 54.2‡33.3 ± 32.5†29.250.0†(1.04 ± 0.70‡ (0.31 ± 0.47)*(0.72 ± 0.76)*G3% Zileuton +2544.021.4 ± 31.5†48.036.0*3% Celecoxib(0.86 ± 0.70)*(0.52 ± 0.58) (0.44 ± 0.65)†All P values were based on comparison with group Bχ2. test was used for analysis of the incidence of lesions. ANOVA test was used for analysis of the number of lesions. Wilcoxon signed rank test was used for analysis of the tumor volume. Fifteen samples from each group were analyzed for LTB4 and PGE2. All P values were based on comparison with group B with Student's t test.*P < 0.01.†P < 0.001.‡P < 0.05.
Based on the limited body of art suggesting the use of COX-2 inhibitors for treating any cancer, and the need for effective treatments for oral cancers in particular, it is apparent that there is a great and immediate need for new compositions for treating oral cancers. This need is met by the inventive methods and compositions, which treat oral cancers without significant side effects.